1. Field of the Invention
The present invention relates to a treating solution for a gold- or gold alloy plated material having nickel or a nickel-containing alloy as an underplating on a metallic material, such as an iron alloy, iron, stainless steel, or high-nickel alloy, and a treating method using the same.
2. Description of the Prior Art
A material comprising brass or phosphor bronze, an underplating of nickel provided thereon, and a gold plating provided on the underplating is generally used as a connector which is a coupling part for electronic equipment. Since, however, gold is expensive, various methods are used for lowering the production cost of connectors. A representative method is to decrease the thickness of the gold plating. This method, however, involves a problem that the number of pinholes created in the gold plating increases exponentially with a decrease in the thickness of the gold plating, resulting in remarkably lowered corrosion resistance.
One method for solving this problem is treating for sealing or the like. According to this method, the surface of the gold plating is treated with various inorganic or organic chemicals to clog the pinholes in the gold plating, thereby improving the corrosion resistance. A treating solution used in such a method is classified into two systems, organic and aqueous. For the organic system, a halogenated organic solvent is generally used as a solvent. Since this poses the problem of the destruction of the ozonosphere and the like, the use of the organic treating solution is greatly restricted at the present time. On the other hand, for the aqueous system, water is used as the solvent, poses no problem of environmental pollution. Since, however, a sparingly water-soluble lubricant, which has been used in conventional organic treating solutions, such as paraffin, cannot be used in the water system, a plating which has been treated with the water system has low lubricity, which renders the durability of connectors treated with the water system inferior to that of connectors treated with the organic solvent system.
Accordingly, a treating solution and a treating method are needed which pose no problem associated with environmental pollution and offer a treating effect equal or superior to that attained by the prior art.